Grounding LFMC

[crispysonofa]

Is it legal to run a peice of LFMC 20 feet from a PVC junction box to a metal enclosure? Would I have to bond the conduit at both ends? Is it not legal to use it with a PVC box in the first place? I will have an EGC in the conduit I am just concerned with bonding the raceway and legality of running from a PVC box.

 

[ramsy]

See 350.60, and note "Shall be permitted" for use as EGC.

 

[infinity]

Is it legal to run a peice of LFMC 20 feet from a PVC junction box to a metal enclosure? Would I have to bond the conduit at both ends? Is it not legal to use it with a PVC box in the first place? I will have an EGC in the conduit I am just concerned with bonding the raceway and legality of running from a PVC box.

Since it contains a EGC and is bonded on one end by the metal box I don't see it as a problem. There will be at least one poster who will see it differently. :angel:

 

[crispysonofa]

as I understand it, listed fittings will properly ground the conduit but wanted to make sure I didn't need a grounding bushing or one of those LFMC connectors with the external ground lug because of bonding on only one side? Here is the scenario, I am feeding a sub panel. I need to run from the main house to the barn. There is only about 1.5' between the structures if that. My plan is to run 6/3 romex to a Jbox in basement then transfer to the LFMC and go out of the house, bury it to 18'' and come up into the new barn sub panel. I was going to just pipe it but I think running the flex in such a tight spot will be easier, plus the local supply house gets like 23 bucks for a single expansion coupling. I know the LFMC is direct burial rated I just don't know if I should pick up a metal box or if I can use a PVC box.

 

[crispysonofa]

I should be clear I am pulling THHN through the LFMC not romex, and I will have 2 hots, 1 neutral and 1 ground.

 

[augie47]

Not a lot of detail given in your plan but be aware of 300.5(D)(4)
(4) Enclosure or Raceway Damage. Where the enclosure or raceway is subject to physical damage, the conductors shall be installed in rigid metal conduit, intermediate metal conduit,
RTRC-XW, Schedule 80 PVC conduit, or equivalent.

 

[crispysonofa]

much appreciated, inspector did not have an issue with the installation. I ended up using a metal box instead of PVC just to be on the safe side. Thank you for the input!